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vconsole: setup_remaining_vcs() - more sanity checks

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Check if values filled up by KD_FONT_OP_GET ioctl make sense -
dummy driver for example doesn't implement required functionality
at all.
This commit is contained in:
Michal Soltys 2016-10-12 18:20:50 +02:00
parent 6b169c13ec
commit 5297577f27
1 changed files with 40 additions and 19 deletions
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59
src/vconsole/vconsole-setup.c
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@ -208,9 +208,9 @@ static int font_load_and_wait(const char *vc, const char *font, const char *map,
*/
static void setup_remaining_vcs(int fd, bool utf8) {
struct console_font_op cfo = {
.op = KD_FONT_OP_GET, .flags = 0,
.width = 32, .height = 32,
.charcount = 512,
.op = KD_FONT_OP_GET,
.width = UINT_MAX, .height = UINT_MAX,
.charcount = UINT_MAX,
};
struct vt_stat vcs = {};
struct unimapinit adv = {};
@ -225,12 +225,6 @@ static void setup_remaining_vcs(int fd, bool utf8) {
return;
}
fontbuf = malloc(cfo.width * cfo.height * cfo.charcount / 8);
if (!fontbuf) {
log_oom();
return;
}
/* get active, and 16 bit mask of used VT numbers */
r = ioctl(fd, VT_GETSTATE, &vcs);
if (r < 0) {
@ -238,19 +232,46 @@ static void setup_remaining_vcs(int fd, bool utf8) {
return;
}
/* get fonts from source console */
cfo.data = fontbuf;
/* get metadata of the current font (width, height, count) */
r = ioctl(fd, KDFONTOP, &cfo);
if (r < 0)
log_warning_errno(errno, "KD_FONT_OP_GET failed, fonts will not be copied: %m");
log_warning_errno(errno, "KD_FONT_OP_GET failed while trying to get the font metadata: %m");
else {
unimapd.entries = unipairs;
unimapd.entry_ct = USHRT_MAX;
r = ioctl(fd, GIO_UNIMAP, &unimapd);
if (r < 0)
log_warning_errno(errno, "GIO_UNIMAP failed, fonts will not be copied: %m");
else
cfo.op = KD_FONT_OP_SET;
/* sanitize parameters first */
if (cfo.width > 32 || cfo.height > 32 || cfo.charcount > 512)
log_warning("Invalid font metadata - width: %u (max 32), height: %u (max 32), count: %u (max 512)",
cfo.width, cfo.height, cfo.charcount);
else {
/*
* Console fonts supported by the kernel are limited in size to 32 x 32 and maximum 512
* characters. Thus with 1 bit per pixel it requires up to 65536 bytes. The height always
* requries 32 per glyph, regardless of the actual height - see the comment above #define
* max_font_size 65536 in drivers/tty/vt/vt.c for more details.
*/
fontbuf = malloc((cfo.width + 7) / 8 * 32 * cfo.charcount);
if (!fontbuf) {
log_oom();
return;
}
/* get fonts from source console */
cfo.data = fontbuf;
r = ioctl(fd, KDFONTOP, &cfo);
if (r < 0)
log_warning_errno(errno, "KD_FONT_OP_GET failed while trying to read the font data: %m");
else {
unimapd.entries = unipairs;
unimapd.entry_ct = USHRT_MAX;
r = ioctl(fd, GIO_UNIMAP, &unimapd);
if (r < 0)
log_warning_errno(errno, "GIO_UNIMAP failed while trying to read unicode mappings: %m");
else
cfo.op = KD_FONT_OP_SET;
}
}
}
if (cfo.op != KD_FONT_OP_SET) {
log_warning("Fonts will not be copied to remaining consoles");
}
for (i = 1; i <= 63; i++) {